1. Field of the Invention
The invention relates generally to a touch module and a touch display panel, and more particularly, to an optical touch module and an optical touch display panel.
2. Description of Related Art
As information technology, wireless mobile communication, and information electric appliances rapidly develop in the recent years, the input devices for a great many information electronic products have been changed from conventional keyboards and mice to touch panels for the purposes of convenience, miniaturization, and being user-friendly. Moreover, a touch panel have been integrated with a display to form a touch panel display. Touch sensing panels can be categorized into resistance touch panels, capacitance touch panels, optical touch panels, sound wave touch panels, and electromagnetic touch panels, etc, based on differences in the sensing principles.
FIG. 1 is a schematic circuit diagram of a conventional photo sensor array. Referring to FIG. 1, FIG. 1 illustrates a photo sensor array 100 disclosed by Taiwan Patent No. 1291237, adopting an in-cell photo sensor touch panel technique, in which the photo sensor is embedded in the touch panel. The photo sensor array 100 employs a current sensing technique to monitor current changes for each of the photo sensors, thereby determining a touch position. As shown in FIG. 1, the photo sensor array 100 includes phototransistors 111, 113, 115, and 117. The phototransistors 111 and 113 are controlled to turn on by a scan signal transmitted by a scan line GL1, whereas the phototransistors 115 and 117 are controlled to turn on by a scan signal transmitted by a scan line GL2. When the phototransistor 111 is turned on, different magnitudes of a current I1 are generated by the phototransistor 111 to a data signal line DL1 according to the strength of a received light. The magnitude of the current I1 is approximately 10-20 μA. Due to the small magnitude of the current I1, an interference due to noise may be easily imposed. Therefore, after the current I1 is amplified by an amplifier module 10, an amplifier module 20 is required to perform a high frequency noise filtering. Moreover, if an optical stylus is used for the touch control, then an amplifier module 30 is required to perform a specific frequency amplification.